15y software dev experience – what to learn for a shift to ML?

Experienced software dev here with ~15 years of experience mostly on the backend side, lots of DB and data handling experience, but not really ML. Want to get into ML Engineering or Data Engineering/Data Science.

Which sources, guides or roadmaps would you suggest I have a look at to learn important frameworks? I know pandas. So would Spark, Databricks be valuable knowledge? Where do I start? Maybe a list of what all is out there could help, too.